Yet Another Solar Powered Airship, this time Purdue is doing it.
It's amusing how many times this comes up and people think it's a novel concept. It's been around for quite a while and no one has yet to do it.
The article concludes with:
Engineers are not yet certain how large the airship might be, but it may be as long as 300 meters, or around 900 feet - roughly four times the length of the Goodyear blimp. A major challenge will be finding materials for the airship's skin that are capable of withstanding the extreme ultraviolet radiation at such high altitudes for extended periods, Sullivan said.
Same problems, different group. Keep at it boys.